Study of establishment and regeneration of forest by DNA polymorphism analysis and isotopic tracer

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The present research accumulated knowledge about the reproduction mechanisms of trees and ectomycorrhizal fungi. Such knowledge accumulation would lay the basis for new methods of natural forest regeneration that stand at the viewpoints of genetic diversity preservation and application of symbiotic function of ectomycorrhizal fungi. Outcomes of the present research are summarized as follows :1. Reproduction mechanisms of trees : Microsatellite polymorphism analyses revealed reproduction mechanisms of several pioneer plants, such as Polygonum cuspidatum and Salix reinii, in volcanic desert on Mount Fuji, and a pioneer tree, Robinia Pseudoacacia in a dry riverbed. The balance between sexual and asexual reproductive manners in a tropical pioneer tree Melaleuca cajuputi was also investigated. The results indicated that the balance was influenced by environmental conditions. The genetic differentiation of a mangrove tree Rhizophora stylosa in Okinawa was also investigated.2. Reproduction me … More chanisms of ectomycorrhizal fungi : In a Larlx stand, we investigated the reproduction mechanism of Suillus grevillei, and found that its extraradical mycelia are present patchily under individual sporocarps and degraded within one year. Also, underground mycorrhizal communities were composed of patches of mycorrhizal mycelia, forming a mosaic. In the volcanic desert on Mount Fuji, we found a lot of ectomycorrhizal sporocarps and root tips, and that primary vegetation succession was accompanied with succession of the ectomycorrhizal fungal community. In this site, fungal species composition among ectomycorrhizae is rather consistent with that among sporocarps. Microsatellite analysis of Scleroderm bovista showed that this fungus first establishes its genet s at the periphery of vegetation patches by accidental long-distance spore dispersal and thereafter expands its occupation by extension of extraradical mycelia. Planting experiments of host tree seedlings on various places of the desert demonstrated that established ectomycorrhizal host trees facilitate the growth and survival of new seedlings.3. Tracer experiments in ectomycorrhizal symbiotic system : We traced the photosynthates in an ectomycorrhizal symbiotic system after feeding ^<14>CO_2 by autoradiography with imaging plates, and obtained some interesting findings on photosynthate translocation to extraradical mycelia.4. Improvements of DNA polymorphic analyses : We first introduced successfully Terminal-RFLP into identification of fungal species. Also, a new technique that enabled everyone to develop micorsatellite markers much easily was established. This technique can be applied to a wide range of species. Less